1. Field of the Invention
The invention relates to air blowers and more particularly to an air blower having a noise absorption device for converting absorbed acoustic energy into heat.
2. Description of Related Art
Typically, a centrifugal blower can be either a spiral air blower having an inlet and an outlet at angle of about 90-degree with respect to the inlet, or a linear air blower having both inlet and outlet arranged in a straight line. Both types of centrifugal blower have an impeller for generating high air pressure and are applicable to air blowers having a narrow outlet or complicated pipes. They are also widely used in heat sinks of electronic devices, automotive air conditioners, or building pipelines. However, the high air pressure may cause turbulence and spiral airflow, resulting in making noise having different frequencies. To the worse, maximum noise can be generated when frequency of vibration obtained by multiplying the number of blades by revolutions per second.
Thus, the need for improvement still exists.